644045002 has 8 divisors (see below), whose sum is σ = 967345956. Its totient is φ = 321596352.

The previous prime is 644044987. The next prime is 644045041. The reversal of 644045002 is 200540446.

It can be written as a sum of positive squares in 2 ways, for example, as 534025881 + 110019121 = 23109^2 + 10489^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 211183 + ... + 214210.

Almost surely, 2^644045002 is an apocalyptic number.

644045002 is a deficient number, since it is larger than the sum of its proper divisors (323300954).

644045002 is a wasteful number, since it uses less digits than its factorization.

644045002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 426152.

The product of its (nonzero) digits is 3840, while the sum is 25.

The square root of 644045002 is about 25378.0417290224. The cubic root of 644045002 is about 863.5856253788.

Adding to 644045002 its reverse (200540446), we get a palindrome (844585448).

The spelling of 644045002 in words is "six hundred forty-four million, forty-five thousand, two".